Power driven wrench



Nov. 15, 1955 A. J. BRAME POWER DRIVEN WRENCH Filed June 21, 1954 Am "Im/ 114 H n w a u. a 4 m m 0 & w \W m w 7 1:. FEE a u u H 5 7 u 0 5 n H k4 a w l. 6 6 6 a M w n E 5 p n m w n n ug y.

ALLEN J. BRAME,

INVEN TOR.

B Zfl Aifornev.

United States Patent 9 POWER DRIVEN WRENCH Allen J. Brame, Los Angeles,Calif., assignor to Tubing Appliance Company, Inc., Los Angeles, Calif.,a corporation Application June 21, 1954, Serial No. 437,943 10 Claims.(CI. 81-57) This invention relates to power-actuated wrenches of thetype that incorporate a pawl-actuated rotary socket member. Theinventien is directed to the problem of making such a wrench of simple,compact construction, and at the same time providing a rugged, efiicientand smoothly operating wrench mechanism.

A tool of this type has a handle with a drive-shaft journalledlongitudinally therein for operative connection to a power source andhas a rotary socket member mounted in a shank structure that extendsforward longitudinally from the handle. The problem is to provide withindesirable space limitations a rugged force-multiplying transmission forconverting rotation of the driveshaft about the longitudinal axis of thetool into slower actuation of the socket member about its transverseaxis.

It is not too difiicult to achieve simplicity alone, or ruggednessalone, or compactness alone, or even to achieve all three in a heavybulky tool that is awkward to use. It is a problem, however, to achieveall these ends in a relatively light tool that is of a desirable compactconfiguration.

The invention meets this problem, in part, by incorporating a gear boxin the tool handle adjacent the shank structure. The grip portion of thehandle houses the driveshaft and the gear box provides a flat surfaceappropriately located for thumb pressure by the operator in the normaluse of the wrench. Thus the tool is given a configuration that providesmaximum convenience for the operator and that is conducive to skillfuland timesaving utilization of the tool.

Two beveled gears positioned in spaced face-to-face relationship on atransverse axis in the gear box are actuated by a third beveled gear onthe driveshaft and serve, in turn, to actuate a pair of pawl arms in theadjacent shank structure for rotation of the socket member by ratchetaction. The two beveled gears are provided with crank pins for thepurpose of reciprocating the two pawl arms. Such a mechanism has aminimum number of separately moving operating parts for smooth actuationof the rotary socket member and these parts not only conform to anoptimum tool configuration but also completely utilize the availablespace within the optimum configuration.

The desired speed reduction with corresponding force multiplication isaccomplished accumulatively in this chain of actuating parts. The speedreduction resides first in the fact that the two beveled gears aresubstantially larger in diameter than the co-acting third beveled gearon the driveshaft, second, in the fact that the throw of the crank armis substantially less than the diameter of the pair of beveled gears onwhich they are mounted, and, third, in the fact that the pair of pawlarms advance the rotary socket member only a fraction of a rotation inresponse to a complete rotation of the pair of beveled gears."

The preferred practice of 'the'invention is further characterized by theconcept of operating both pawl arms on the same quadrant of the toothedrotary socket member. With such a pair of pawl arms operating at 180phase relationship to one another, substantially continuous operatingforce is applied to the rotary socket member. Preferably, but notnecessarily, the two pawl arms operate as pusher arms rather than aspuller arms. In this regard, a feature of the preferredpractice of theinvention is the provision of circularly curved recesses between theratchet teeth of the rotary socket member with the ends of the pusherarms correspondingly curved for pivotal bearing against the recesssurfaces.

The features and advantages of the invention may be readily understoodfrom the following detailed description considered with the accompanyingdrawing.

In the drawing, which is to be considered illustrative:

Figure 1 is a plan view of the presently preferred embodiment of thetool, with one gear and a portion of the housing removed to revealconcealed parts;

Figure 2 is a-longitudinal sectional view of the tool;

Figure 3 is a transverse section through the gear box taken on line 3-3of Figure 1;

Figure 4 is a transverse section taken on line 44 of Figure 1, showingthe construction of the rotary socket member; and

Figure 5 is a transverse section taken on the line 5-5 of Figure 1.

The housing of the illustrated embodiment of the invention may beconsidered as comprising, first, a base or grip portion that isconnected to the power source, second, the gear box 11 that cooperateswith the grip portion 10 to form a handle with a convenient thumb rest,and, third, a forwardly extending longitudinal shank portion 12 in theend of which is mounted a suitable rotary socket member 15. The shankportion 12 is of relatively narrow flat configuration to permit the toolto enter narrow spaces and to minimize interference with visibility inthe manipulation of the tool.

The base portion 10 of the tool housing includes a cylindrical body 16that has internal threads 17 at the butt end of the tool for connectionwith a suitable power source such as a pneumatic motor (not shown). Thecylindrical body 16 has a reduced portion 18 at its other end formedwith external threads 20. In the construction shown, the gear box 11 andthe shank portion 12 are unitary or integral with each other but aredivided into two longitudinal sections which mate at parting lines shownat 21 in Figures 3 and 5. These two mating housing sections are heldtogether by a pair of laterally spaced screws 25 in the gear box 11 andby a single central screw 26, in the shank portion 12 near the rotarysocket member 15.

The two mating longitudinal housing sections form a cylinder 27 at oneend which, in the assembled tool, is a part of the base or grip portion10 of the housing. The cylinder 27 has internal threads 28 that normallyengage the previously mentioned external threads 20 of the cylindricalbody 16 with the end of the cylinder 27 in abutment against acircumferential shoulder 30 of the cylindrical body.

The actuating mechanism employed in this embodiment of the inventionconsists essentially of only six separately movable parts, namely: thepreviously mentioned rotary socket member 15 having peripheral ratchetteeth 34; a pair of reciprocative pawl arms 35 and 36 for drivingengagement with the ratchet teeth 34; a pair of beveled gears 37 and 38adapted to reciprocate the two pawl arms respectively; and a driveshaft40 carrying a third beveled gear 41 in mesh with the pair of beveledgears 37 and 38. It is to be understood, however, that the invention inits broader aspects is not restricted-to these specific working parts.

The driveshaft' 40, which has asplined end 45 for connection to a powersource, is rotatably mounted in the cylindrical body 16 by means of aroller bearing 46 and by means of a ball bearing having an inner race 47and an outer race 48. The inner race 47 of the ball bearing abuts theback of the third beveled gear 41 on the end of the driveshaft and theouter race 48 fits against an inner circumferential shoulder 49 of thecylindrical body 16. It is apparent that the beveled gear 41 which isfixed to the end of the driveshaft by a suitable set screw 50 cooperateswith the pair of gears 37 and 38 to hold the driveshaft 40 againstforward axial movement and cooperates with the ball bearing and theinner shoulder 49 to prevent rearward axial movement of the driveshaft.

Each of the two beveled gears 37 and 38 is formed with an outwardlyextending hub 54 that is journalled in a bearing sleeve 55 in a circularaperture 56 in the wall of the gear box 11. Each of the two beveledgears 37 and 38 also backs against a circular series of balls 57confined between an outer race 58 and an inner race 59. The inner race59 embraces an inner cylindrical flange 60 formed in the gear box 11around the corresponding aperture 56. It can be seen that the twobeveled gears 37 and 38 are held apart and in engagement with the twocorresponding series of balls 57 by virtue of their engagement with theintervening gear 41.

The two beveled gears 37 and 38 may be adapted in any suitable mannerfor reciprocating the two pawl arms 35 and 36. For this purpose, each ofthe beveled gears may be provided with an eccentric crank pin 64 that ismounted with a press fit in a bore 65 in the beveled gear. Forcooperation with the two crank pins 64, respectively, the two pawl arms35 and 36 may each be formed with an integral collar 66 that is linedwith a bearing sleeve 67, the bearing sleeve rotatably embracing thecorresponding crank pin 64. Preferably, as shown on the drawing, theeccentric positions of the two crank pins 64 are approximately 180degrees out of phase with each other.

The socket member 15, which opening, as shown in Figure 1, is formedwith two opposite hub portions 68 (Figure 4) which are journalled incorresponding. circular apertures 70 in the opposite walls of the shankportion 12 of the housing. Preferably, the housing is cut away toprovide a window 74, the two opposite ends of which are indicated at and76, respectively, in Figure 1.. Thus the window 74 extends around thenose of the shank portion 12 and exposes the peripheral teeth 34 of therotary socket member 15, as may be seen in Figure 4. This openarrangement makes the interior of the housing accessible for inspectionand oiling.

Both of the two pawl arms 35 and 36 lie to one side of the centralhousing screw 26 for operation on the same quadrant of the rotary socketmember 15. Thus the two pawl arms are confined between the screw 26 andone side wall of the shank portion of the housing. Preferably a sleeve77 encircles the housing screw 26. As shown in Figure 5, the sleeve 77may be held in place by a pair of opposite bosses 78 on the inner wallof the housing. The two pawl arms 35 and 36 are normally urged laterallytowards the sleeve 77 in a yielding manner, for example, by means of aleaf spring 89. The leaf spring 89 is mounted inside the housing by asuitable screw 30 and has two arms pressing against the two pawl arms 35and 36 respectively.

As heretofore indicated, a feature of the preferred practice of theinvention is that the peripheral recesses in the rotary socket member 15that are formed by the series of ratchet teeth 34 have bottom walls ofcircular curvature, and the ends of the two pawl arms 35 and 36 are ofcorresponding configuration to fit snugly therein for cooperativepivotal action through a small angular range. For this purpose, theinner surfaces of the recesses between the ratchet teeth may bespherically driving beveled has the usual hexagonal curved and theoperating ends of the pawl arms may be correspondingly sphericallycurved. Preferably, however, the inner; surfaces 85 of the recesses arecylindrically curved as irjuicated in Figure 1 and the operating end ofeach of the two pawl arms 35 and 36 is formed with a nose or lobe ofsimilar external cylindrical curvature.

in the construction shown, each of the pawl arms is also cut away orslightly recessed on its inner longitudinal edge to permit the desiredcooperation with the rotary socket member 15. The desired configurationof the two pawl arms 35 and 36' may be seen in Figure 1 where the pawlarm 35 is shown at its extreme advanced position. It will be noted thatthe outer longitudinal edge 86 of the pawl arm is at this timesubstantially tangential to the circle defined by the tips of theratchet teeth 34, and that the inner longitudinal side of the pawl armis formed with a shallow \l-shaped recess with its vortex at 87 so thatthe nose or lobe at the end of the pawl arm conforms at this moment.with the slope of the back of the next successive ratchet tooth 34.

Figure 1 shows the second pawl arm 36 just as it begins its approachinto operative contact with the rotary socket member 15. As the end ofthe pawl arm makes initial seating contact with the cylindrically curvedbottom surface 85 of the recess between two of the ratchet teeth 34, theside of the pawl arm diverges at a slight angle from the sloping back ofthe next successive ratchet tooth. As the pawl arm makes itslongitudinal thrust, it pivots cylindrically in the bottom of the recessand the angle between the surface of the pawl and the back of the nextsuccessive ratchet tooth progressively closes as the pawl arm reachesits outer limit position.

It is apparent that the two pawl arms 35 and 36 will operate alternatelyfor intermittent rotary advancement of the socket member 15 with only aslight pause between each advance. Since each thrust of a pawl arminvolves a transmission of force by the seating of a curved surface of apawl arm in a similarly curved recess of the ratchet member, the wearingaction is distributed rather than concentrated, and, moreover, thedesired complementary curvatures of the surfaces of the pawl arms and ofthe ratchet recesses tends to be maintained by the wearing action.

My description of the selected embodiment of the invention, by way ofexample and to illustrate the principles involved, will suggest variouschanges, substitutions and other departures from my disclosure thatproperly lie within the spirit and scope of the appended claims.

I claim:

1. In a power wrench of the character described, the combination of: ahousing; a socket member rotatably mounted in said housing, said socketmember having peripheral ratchet teeth; a pair of pawl arms positionedand adapted for engagement with said ratchet teeth in the same quadrantof the socket member; and poweractuated means to reciprocate said pawlarms for driving said socket member, said power actuated means includingtwo rotary eccentric members substantially degrees out of phase witheach other for alternate operation of said two pawl arms.

2. In a power wrench of the character described, the combination of: ahousing; a socket member rotatably mounted in said housing, said socketmember having peripheral ratchet teeth; a pair of pawl arms positionedand adapted for engagement with said ratchet teeth in the same quadrantof the socket member and power-actuated means to reciprocate said pawlarms for driving said socket member, said power actuated means includingtwo beveled gears having eccentric elements in operating engagement withsaid pair of pawl arms respectively.

3. A power wrench as set forth in claim 2 in which said power-actuatedmeans includes a driveshaft having a beveled gear thereon in engagementwith said pair of beveled gears.

4. A power wrench of the type described, comprising: a housing; a drivenmember rotatably mounted in said housing, said driven member havingperipherially arranged ratchet teeth; a pair of pawl arms positioned andadapted for thrust engagement with said ratchet teeth in the samequadrant of the driven member; and power-actuated means to alternatelyreciprocate said pawl arms, each arm applying a pushing thrust to saidratchet teeth engaged thereby at each reciprocation of the arm, wherebysaid driven member is rotatably driven.

5. A power wrench of the type described, comprising: a housing; a drivenmember rotatably mounted in said housing; an annular series of ratchetteeth peripherally formed about said driven member; a pair of pawl armspositioned and adapted for engagement with said ratchet teeth in thesame quadrant of the driven member; poweractuated means operativelyconnected to each of said pawl arms and operable to alternatelyreciprocate said arms; and power means for actuating said last namedmeans, whereby said power-actuated means alternately reciprocate saidarms to urge the same into driving engagement with said ratchet teeth torotatably drive said driven member.

6. A power wrench of the type described, comprising: a housing; a drivenmember rotatably mounted in said housing, said driven member havingperipherally arranged ratchet teeth; a pair of pawl arms positioned andadapted for thrust engagement with said ratchet teeth in the samequadrant of the driven member; power-actuated means operativelyconnected to each arm at one end thereof for alternately reciprocatingsaid arms to alternately thrust the free ends of said arms intoengagement with said ratchet teeth in a path substantially tangentialthereto; and resilient means mounted on said housing and engaged withsaid arms for yieldably holding the free ends of said arms in engagementwith said teeth.

7. A power wrench of the type described, comprising: a housing; a drivenmember; support means for rotatably mounting said member on saidhousing; an annular series of ratchet teeth peripherally formed aboutsaid driven member; a pair of pawl arms; eccentric means operativelyconnected to an end of each arm for reciprocatively driving each of saidpawl arms; means for guiding said pawl arms and yieldably holding thefree ends thereof in engagement with said ratchet teeth in the samequadrant of said driven member; and power means for operating saideccentric means so that said eccentric means alternately reciprocatessaid pawl arms to alternately thrust 6 the free ends of said arms intodriving engagement with said ratchet teeth to rotatably drive saiddriven member.

8. A power wrench of the type described, comprising: a housing; a drivenmember rotatably mounted in said housing, said driven member havingperipherally at" ranged ratchet teeth; a pair of pawl arms positionedand adapted for thrust engagement with said ratchet teeth in the samequadrant of the driven member; eccentric means operatively connected toeach arm and adapted, when actuated, to alternately reciprocate saidarms; and poweractuated means including a rotatable drive elementoperatively connected to said eccentric means for actuating the same,said eccentric means completing a reciprocation of each pawl arm foreach revolution of said rotatable drive element whereby said pawl armsthrustingly engage with said teeth twice for each revolution of saiddrive element to rotatably drive said driven member.

9. In a power wrench of the character described, the combination of: ahousing having a grip portion, a gear box portion adjacent said gripportion, and a shank portion extending from said gear box portion; asocket member having ratchet teeth and mounted rotatably in the outerend of said shank portion of the housing; a pair of pawl arms extendingfrom said gear box portion of the housing through said shank portion foroperative engagement with said ratchet teeth; a pair of beveled gearspositioned face-to-face in said gear box portion of the housing, each ofsaid beveled gears having an eccentric element thereon in operativeengagement with said pawl arms respectively; a drive shaft extendinglongitudinally through said grip portion of the housing; a beveled gearon said driveshaft in mesh with said pair of beveled gears; and yieldingmeans exerting force against said pawl arms laterally thereof to urgethe pawl arms into engagement with said ratchet teeth of the rotarysocket member.

10. A power wrench as set forth in claim 9 in which both of said pawlarms are pusher arms extending to one side of the longitudinal axis ofsaid housing to act on the same quadrant of said rotary socket member.

References Cited in the file of this patent UNITED STATES PATENTS714,586 Landis Nov. 25, 1902 1,254,587 Erickson Jan. 22, 1918 2,119,968Shafi June 7, 1938 2,264,012 Wassom Nov. 25, 1941 2,491,624 Shaft Dec.20, 1949 2,505,889 Foreman May 2, 1959

